GCC on PowerPC has no option `-march`

The octopus configure wrapper adds -march=... to CFLAGS, CXXFLAGS and FCFLAGS. This causes the configure call on PowerPC to fail because an unknown option is passed. Removing -march from the flags resolves the problem.

In the config.log gcc suggests that maybe we intended to use -mcpu instead. I don't know if this would be the correct flag for PowerPC or if we can just omit it entirely.

Supported flags on PowerPc are (output from man gcc):

RS/6000 and PowerPC Options -mcpu=cpu-type -mtune=cpu-type -mcmodel=code-model -mpowerpc64 -maltivec  -mno-altivec -mpowerpc-gpopt  -mno-powerpc-gpopt -mpowerpc-gfxopt  -mno-powerpc-gfxopt -mmfcrf  -mno-mfcrf  -mpopcntb  -mno-popcntb  -mpopcntd  -mno-popcntd -mfprnd  -mno-fprnd -mcmpb  -mno-cmpb  -mhard-dfp  -mno-hard-dfp -mfull-toc   -mminimal-toc  -mno-fp-in-toc
           -mno-sum-in-toc -m64  -m32  -mxl-compat  -mno-xl-compat  -mpe -malign-power  -malign-natural -msoft-float  -mhard-float  -mmultiple  -mno-multiple -mupdate  -mno-update -mavoid-indexed-addresses  -mno-avoid-indexed-addresses -mfused-madd  -mno-fused-madd  -mbit-align  -mno-bit-align -mstrict-align  -mno-strict-align  -mrelocatable -mno-relocatable  -mrelocatable-lib
           -mno-relocatable-lib -mtoc  -mno-toc  -mlittle  -mlittle-endian  -mbig  -mbig-endian -mdynamic-no-pic  -mswdiv  -msingle-pic-base -mprioritize-restricted-insns=priority -msched-costly-dep=dependence_type -minsert-sched-nops=scheme -mcall-aixdesc  -mcall-eabi  -mcall-freebsd -mcall-linux  -mcall-netbsd  -mcall-openbsd -mcall-sysv  -mcall-sysv-eabi  -mcall-sysv-noeabi
           -mtraceback=traceback_type -maix-struct-return  -msvr4-struct-return -mabi=abi-type  -msecure-plt  -mbss-plt -mlongcall  -mno-longcall  -mpltseq  -mno-pltseq -mblock-move-inline-limit=num -mblock-compare-inline-limit=num -mblock-compare-inline-loop-limit=num -mno-block-ops-unaligned-vsx -mstring-compare-inline-limit=num -misel  -mno-isel -mvrsave  -mno-vrsave -mmulhw
           -mno-mulhw -mdlmzb  -mno-dlmzb -mprototype  -mno-prototype -msim  -mmvme  -mads  -myellowknife  -memb  -msdata -msdata=opt  -mreadonly-in-sdata  -mvxworks  -G num -mrecip  -mrecip=opt  -mno-recip  -mrecip-precision -mno-recip-precision -mveclibabi=type  -mfriz  -mno-friz -mpointers-to-nested-functions  -mno-pointers-to-nested-functions -msave-toc-indirect
           -mno-save-toc-indirect -mpower8-fusion  -mno-mpower8-fusion  -mpower8-vector  -mno-power8-vector -mcrypto  -mno-crypto  -mhtm  -mno-htm -mquad-memory  -mno-quad-memory -mquad-memory-atomic  -mno-quad-memory-atomic -mcompat-align-parm  -mno-compat-align-parm -mfloat128  -mno-float128  -mfloat128-hardware  -mno-float128-hardware -mgnu-attribute  -mno-gnu-attribute
           -mstack-protector-guard=guard -mstack-protector-guard-reg=reg -mstack-protector-guard-offset=offset -mprefixed -mno-prefixed -mpcrel -mno-pcrel -mmma -mno-mmma -mrop-protect -mno-rop-protect -mprivileged -mno-privileged